Generally, existing common oriented silicon steel (CGO) uses MnS or MnSe as an inhibitor and is produced by adopting a two-time cold-rolling method. The two-time cold-rolling method comprises the following main production process:
smelting; hot-rolling; normalizing; primary cold-rolling; intermediate annealing;
secondary cold-rolling; decarbonizing and annealing; high-temperature annealing; and
coating an insulation layer. The key technical points thereof are as follows:                Smelting: a slab is formed by performing steel making in a converter (or an electric furnace), performing secondary refining and alloying, and performing continuous casting, wherein the slab comprises the following basic chemical components by weight percent: 2.5-4.5% of Si, 0.02-0.10% of C, 0.025-0.25% of Mn, 0.01-0.035% of S or Se, not more than 0.01% of Al, not more than 0.005% of N, one or more of Cu, Mo, Sb, B, Bi and other elements which are contained in some component systems and the balance of iron and inevitable impurity elements.        Hot-rolling: generally, the slab is heated to the temperature of 1350° C. or more in a special high-temperature heating furnace, and is kept at the temperature for 45 min or more to realize full solid solution of a favorable inclusion MnS or MnSe and then 4-6 passes of rough rolling and finish rolling are performed. Through fast cooling between finish rolling and coiling, carbides can be dispersed and distributed in grains, thereby being favorable to obtaining small and uniform primary grains.        Normalizing: keeping at 850-950° C. for 3 min such that the structure of a hot-rolled plate is more uniform.        Primary cold rolling: the cold rolling reduction ratio is 60-70% and 3-4 passes of rolling are performed.        Intermediate annealing: the intermediate annealing temperature is 850-950° C. and the annealing time is 2.5-4.0 min.        Secondary cold-rolling: the secondary cold rolling reduction ratio after intermediate annealing is 50-55% and the number of passes of cold rolling is 2-3.        Decarbonizing and annealing: primary recrystallization is completed and secondary grain-shaped core points are formed after decarbonizing and annealing. The C content is removed till 30 ppm or less, thereby ensuring to be in a single a phase during subsequent high-temperature annealing, developing a perfect secondary recrystalized structure and eliminating magnetic aging of a finished product.        High-temperature annealing: the high-temperature annealing must be performed firstly to perform secondary recrystallization to grow secondary grains and then a layer of magnesium silicate bottom layer glass film is formed on the surface of a steel strip; and purifying and annealing are finally performed to remove S, N and other elements which are decomposed from the inhibitor and are harmful to magnetic property, and thus the common oriented silicon steel with high degree of orientation and ideal magnetic performance is obtained.        Insulating coating: by applying an insulating coating and performing stretching and annealing, an oriented silicon steel product in a commercial application form is obtained.        
A Chinese patent document with publication number of CN1321787A and publication date of Nov. 14, 2001, entitled “Single-oriented electrical steel sheet and preparation method thereof”, discloses a single-oriented electrical steel plate and a manufacturing method thereof. The manufacturing procedure of the method comprises the following steps: smelting raw materials, wherein the raw materials comprise the following chemical components by weight percent: 0.02-0.15% of C, 1.5-2.5% of Si, 0.02-0.20% of Mn, 0.015-0.065% of acid-soluble Al, 0.0030-0.0150% of N, 0.005-0.040% of one or two of S and Se, and the balance of Fe and other inevitable impurities; annealing a hot-rolled plate coil at the temperature of 900-1100° C., performing primary cold-rolling, decarbonizing, annealing, final annealing and final coating so as to obtain the electrical steel plate with the plate thickness of 0.20-0.55 mm and the average crystal grain size of 1.5-5.5 mm, wherein the iron loss value W17/50 satisfies that the formula: 0.5884e1.9154×plate thickness(mm)≦W17/50(W/kg)≦0.7558e1.7378×plate thickness(mm), and the value of B8 (T) satisfies the formula: 1.88≦B8(T)≦1.95.
A US patent document with publication number of U.S. Pat. No. 5,039,359 and publication date of Aug. 13, 1991, entitled “Manufacturing method of grain oriented electrical steel plate with excellent magnetic property”, relates to a manufacturing method of an electrical steel plate with excellent magnetic property, and the manufacturing method comprises the following steps: smelting molten steel, wherein the molten steel comprises the following chemical components by weight percent: 0.021-0.100 wt % of C and 2.5-4.5 wt % of Si, as well as a silicon steel plate forming inhibitor, and the balance of iron and other inevitable impurities; forming a hot-rolled and coiled steel plate, wherein the coiling and cooling temperature is not more than 700° C., and the temperature is lower 80% or more than the actual temperature of the hot-rolled and coiled steel plate; balancing one or more elements in the composition of a working table of the hot-rolled steel plate; and performing at least one time cold-rolling for producing the oriented silicon steel, wherein the magnetic induction of the product can be 1.90 T or more.
A US patent document with publication number of U.S. Pat. No. 5,472,521 and publication date of Dec. 5, 1995, entitled “Manufacturing method of grain oriented electrical steel plate with excellent magnetic property”, discloses a manufacturing method of an electrical steel plate with improved magnetic property and stable grain orientation. Oriented silicon steel is produced by adopting a low-temperature slab heating technology and a normalizing-free primary cold-rolling process, and the patent simultaneously relates to the relation of nitrogen content after smelting and magnetic induction of the steel plate.
The above prior arts having following shortcomings:
(1) MnS or MnSe is adopted as a main inhibitor, thereby resulting in relatively low magnetic property of a finished product;
(2) in order to realize full solution of the MnS or MnSe inhibitor, the highest heating temperature needs to reach 1400° C., which is the limit level of a traditional heating furnace; in addition, due to high heating temperature and great burning loss, the heating furnace needs to be repaired frequently and the utilization rate is low; and meanwhile, because high heating temperature leads to high energy consumption and edge crack of a hot-rolled coil is large, in the cold-rolling procedure, it is difficult to produce, the yield is low and the cost is high;
(3) under the existing chemical component system, a common oriented silicon steel finished product with a suitable magnetic property can be obtained only when the whole production process uses normalizing, intermediate annealing and a secondary cold-rolling method, which results in complicated procedure, long manufacturing process flow and over-low production efficiency; and
(4) MnS or MnSe is complete solid-soluble non-nitriding type in the existing common oriented silicon steel, and because the reheating temperature of a slab is too high in the actual production thereof, the strength of the inhibitor in the slab is non-uniform, and it easy to generate coarse grains and the like, which results in the problems of imperfection of the secondary recrystallization, reduced magnetic induction and the like.